Flat displays are developed very rapidly due to its characteristics such as ultrathin thickness and energy-saving. Most flat displays adopt shift registers. At present, shift registers implemented in a Gate on Array (GOA) technique can not only be integrated on a gate driving integrated circuit, but also allow to reduce one manufacturing process of a display panel, thus saving cost. As a result, in recent years, the GOA technique is widely applied to the manufacturing process of the flat display.
The existing problem in the GOA technique is in that a present stage of shift register implemented in the GOA technique depends on an output signal of a previous stage of shift register, that is, since the output signal of the previous stage of shift register functions as an input signal of the present stage of shift register, and if an exception occurs in the output signal of the previous stage of shift register due to a failure or an invalidation of the previous stage of shift register, subsequent shift registers cannot output signals properly; that is to say, such a case can result in that the whole GOA circuit malfunctions, and even cannot operate.
Further, in an actual production manufacturing, since it is difficult for a yield ratio of a Thin Film Transistor (TFT) backboard to reach 100%, it is possible that a defect occurs in the TFTs of a shift register in the GOA circuit, which can lead to the failure of the shift register, and thus it can result in a breakdown of the whole GOA circuit.